Electric switch.



C. A. PALMGREN.

ELECTRIC SWITCH.

.APPLICATION FILED JULY'Z. 1915.

1,173,460., V Patented Feb. 29,1916.

. 3 SHEETS-SHEET I.

C A. PALMGREN.

ELECTRIC SWITCH.

APPLICATION FILED JULY 2,1915.

Patented Feb. 29, 1916.

3 SHEETS-SHEET 2.

C. A. PALMGREN. ELECTRIC SWITCH.

APPLICATION FILED JULY 2.1915.

1,173,460 I Pa tentd Feb. 29,1916.

3 SHEETS-SHEET 3.

UNITED STATES PATENT GFFICE.

CARL A. PALMGREN', OF CHICAGO, ILLINOIS.

Application filed July 2, 1915.

To all whom it may concern. I,

Be it known that I, CARL A. PALMGREN, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Electric Switches, of which the following is a. specification.

My invention relates to electrical switches and. has particular refer'enceto a novel switch for use in connection with registering pyrometers.

In steel plants andother manufacturing establishments in which metals are heat treated, it is common to employ recording pyrometers, a. e., pyroi'neters located in the heating furnaces and to electrically con iiect these pyrometers with a recording de= which shall automatically make the circuit with the difierent furnaces alternately,

whereby the temperature of each furnace may be recorded for a portionof the time during each hour. For instance, assuming four furnaces connected to a single recording device, each furnace would be connected with the recording device for fifteen minutes during the hour. The number of furnaces may be increased or diminished, as desired,

it being certain, however, that irrespective of the number offurnaces, the temperature of each furnace will be recorded for a period of time during each hour, the length of time over-"which record is made depending upon the number of furnaces in action. Th 1s result is secured by connectin the switching mechanism, to a clockriven shaft, the speed of rotation of which corresponds to that of the minute-hand of the clock. If'desired, of course, the shaft might be made to revolve one or more times faster,

in which case a record might be made of each furnace at shorter intervals, such rec- 0rd, of course, being of shorter duration than in the case mentioned. I a

' The invention willbe more readily understoodv byreference to the accompanying drawings, wherein Specification of Letters Patent.

ETJEGTRIG SWITCH.

Patented Feb. 29, 1916.

Serial No. 37,643.

Figure 1 is a sectional View through a switch constructed in accordance with my invention; Fig.2 is a sectional view through the casing showing the switch mechanism in elevation; Fig. 3 is an enlarged plan view of the pivoted contact pieces; Fig. 4 is a sectional view through a slightly modified construction; Fig. 5 is a fragmentary plan view of the construction shown in Fig. 4; Fig. 6 is a section through one of the'mercury troughs of Fig. 1; Fig. 7 is an enlarged sectional detail of one of the cam-operated parts of the mechanism; Fig. 8 is a detailed elevation of a still further modification; Fig. 9 is an elevation of the construction shown in Fig. 8, and Fig. 10 is a front view of a clock showing the divisions on the face thereof according to the number of furnaces served by the device.

Referring more 'jarticularly to Figs. 1, 2 and 3, it will be seen that my device is intended. to be associated with a clock 10, a shaft 11 of which is operated at a speed substantially equal to that of'the minutehand of the clock. This is according to the nally on the shaft and located-at 90 from each other. The present device is shown as connected to and serving four furnaces, these furnaces being indicated, for convenience, as 17, 18, 19 and 20, as shown in Fig. 1Q, the intention being that the temperature of each of the four furnaces shall be recorded for a period of fifteen minutes. The mechanism by which the desired result is secured may consist of a recording pyrometer of any approved form and which is not here shown, suitable electrical connections be tween the pyrometer, the switch of this invention and the furnaces. tion of Figs. 1 to 3 the switch mechanism is shown as comprising a shaft 21 pivoted in the frame member 12 andcarrying a plurality of bearings 22 of insulating material, to which metallic arms 23 are secured. Two arms constitute a unit, it being intended to illustrate four units, one of which is connected to each furnace. A pair'of arms 23 are united at their rear ends, as best shown in Fig. 7, by means of the U-shaped part 24, the.

In the construcmaterial. The head 25 of the member is adapted to contact with one of the cams 13 to 16 inclusive. -Spring members 26 bear upon the arms 23 and tend to force the member 24 in a downward direction. At the forward terminal of the arms 23, I provide sci nv contact pieces 27,28,which are adapted to bear upon contact plates 29, 30, which plates are pivoted to the brackets 31 and urged into elevated position by means of the springs 32, connected to short levers 33 on the ends of-the contact plates. An electrical connection 34, 35 is provided for each of the contact plates 29, 30, these connections extending to the recording pyrometer (not shown). Electrical connections 36, 37 extend to the heat measuring instrument located in the furance served by that unit.

. In Figs. a and 6 the connections to the scending screw pyrometer and furnace are shown more fully. As will be noted in that figure, I have provided terminals for electrical connections with four furnaces, indicating the number of the furnace in a circle above each of the pairs of terminals.

In the modified Figs. 4, 5 and 6 all the parts remain the same except in that the contact plates shown in Fig. 3 are eliminated and in place thereof I have substituted troughs 38, 39, adapted to be filled with mercury, and into which the lower ends of the screw contact pieces are adapted to project.

In the construction of F igsQ 8 and 9 I have shown a still further modification of the contact pieces. In that construction the wires leading to the pyrometer terminate in'plate's 4O, 41, having a plurality of spring contact pieces 42, 43 thereon with which the screw contacts may engage.

An advantage in the construction shown Figs. '1 to 3 is in that no time is lost within which the temperature of no furnace is being recorded, for the reason that as thecOntact pieces of one unit are being elevated the contact plates 29, 30 will follow the pieces until they engage the de-. contacts of the next'unit. In that way no time is lost.

As explained, the number of furnaces controlled or acting upon the recording pyrometer is not limited, as the shaft 11 may be Copies of this patent may be obtained for five cents each, by addressing the terval of time.

construction shown in i pivoted contact of June, 1915.

provided with any desired number of cams. In case a larger number of furnaces is served, the length of time in which the record is made will be lessened, although it would be entirely practical to of the shaft 11 and make a recordof each furnace a number of times during each hour, such a record being made for a shdrterin- Obviously also other'modifications may be madein the construction than those herein shown, and such modifications as are withinthe scope of my claim I consider within the spirit of my invention.

I claim: I

1. In a device of the class described, the combination of a plurality of pairs of pivoted contact pieces, each pair of which is adapted to be connected to a heat measuring device, a single pair of pivoted contact pieces adapted to be connected to a re cording device, and means for moving said first-mentioned pairs of contact pieces into engagement with said second contact pieces, said means including a time-controlled shaft and spaced cams on said shaft so arranged as to bring said pairs of contact pieces into action in sequence, substantially as described.-

2. In a device of the class described, the combination of a plurality of pairs of pieces, each pair of which is adapted to be connected to a heat measurlng device, a single pair of pivoted con tact pieces adapted to be connected to a recording device, a time-controlled. shaft adapted for one complete rotation during each hour, a cam on said shaft for each of said plurality of pairs of contact pieces, the total effective area of said cams being 360, said cams being spaced on said shaft and an. gularly spaced, whereby each of said plurality of pairs of contact pieces is actuated once during each hour, the length of actuation being controlled by the number of these measuring-devices which are served, substantially as described.

Signed at Chicago, Illinois, this 25th day CARL A. PALMGREN.

Witnesses: A. J. DREW,

D. V. MEDALIE.

"Commissioner of Patents,

Washington, D. .0.

increase the speed 

